Growth in the number of applications and subsequent awards for Social Security disabled-worker benefits marked the period from 1986 through 1993. These increases resulted in the 37 percent rise in the number of disabled-worker beneficiaries, 6 out of 10 of whom had disabilities within three diagnostic groups: circulatory disorders; mental disorders (other than mental retardation); and musculoskeletal diseases. The percentage of disabled workers with a circulatory condition decreased from 21 to 14 percent, while the percentage with a mental disorder increased from 20 to 25 percent, and the percentage with musculoskeletal conditions increased from 18 to 21 percent. Musculoskeletal conditions (22 percent) were the leading diagnosis among disabled widows and widowers in 1993, while the disabled adult child population was dominated by the mental retardation diagnostic group (63 percent). Variations in diagnostic conditions of disabled workers by sex, age, and region were often substantial.